Monday, February 15, 2010

VITAMIN E

VITAMIN E


Other Names:
All Rac-Alpha-Tocopherol, Alpha-Tocopherol, Alpha Tocopherol Acetate, Alpha Tocopheryl Acetate, d-Alpha-Tocopherol, d-alpha Tocopherol, d-Alpha Tocopheryl Acetate, d-Alpha-Tocopheryl Acid Succinate, d-Alpha Tocotrienol, dl-Alpha-Tocopherol, d-Beta-Tocopherol, d-Delta-Tocopherol, d-Gamma-Tocopherol, d-Gamma Tocotrienol, Fat-Soluble Vitamin, Mixed Tocopherols, RRR-Alpha-Tocopherol, Tocopherol, Mixed Tocotrienols, Tocotrienol, Beta-Tocopherol, Delta-Tocopherol, Gamma-Tocopherol, Alpha Tocotrienol, Beta Tocotrienol, Delta Tocotrienol, Gamma Tocotrienol, Palm Tocotrienols, Tocopherol Acetate, Tocopheryl Acetate, Tocotrienols, Vitamin E Acetate, Vitamin E Succinate.

Vitamin E exists in eight different forms ("isomers"): alpha, beta, gamma, and delta tocopherol; and alpha, beta, gamma, and delta tocotrienol. Alpha-tocopherol is the most active form in humans. Dosing and daily allowance recommendations for vitamin E are often provided in Alpha-Tocopherol Equivalents (ATE) to account for the different biological activities of the various forms of vitamin E, or in International Units (IU), which food and supplement labels may use. Vitamin E supplements are available in natural or synthetic forms. The natural forms are usually labeled with the letter "d" (for example, d-gamma-tocopherol), whereas synthetic forms are labeled "dl" (for example, dl-alpha-tocopherol).

Vitamin E is a fat-soluble antioxidant that stops the production of ROS formed when fat undergoes oxidation. [1] Dietary and supplemental vitamin E is absorbed and delivered to the liver, but of the various antioxidants with vitamin E activity, only alpha-tocopherol is preferentially recognized by the alpha-tocopherol transfer protein (alpha-TTP) and is transferred to plasma, while the other vitamin E forms (e.g., gamma-tocopherol or tocotrienols) are removed from the circulation. Hepatic alpha-TTP is required to maintain plasma and tissue alpha-tocopherol concentrations. The liver is the master regulator of the body's vitamin E levels in that it not only controls alpha-tocopherol concentrations, but also appears to be the major site of vitamin E metabolism and excretion. Vitamin Es are metabolized similarly to xenobiotics they are initially omega-oxidized by cytochrome P450s, undergo several rounds of beta-oxidation, and then are conjugated and excreted. As a result of these various mechanisms, liver alpha-tocopherol and other vitamin E concentrations are closely regulated; thus, any potential adverse vitamin E effects are limited. [Traber MG, Annu Rev Nutr. 2007;27:347-62]

Vitamin E is an important component of our antioxidant system. It is considered a master antioxidant because: [Papas AM. The Vitamin E Factor, HarperCollins Publishers, Inc., New York, NY. 1999]
  1. Tocopherols and tocotrienols are chain-breaking antioxidants – they break the chain reaction of lipid peroxidation, the process that turns lipid rancid.
  2. The structure of vitamin E makes it unique and indispensable in protecting cell membranes. Vitamin E, primarily alpha-tocopherol, anchors itself strategically in the membrane with the hydrophobic (water hating) tail in the interior of the membrane. The hydrophilic (water loving) head is in the hydrophilic area of the membrane.
  3. Vitamin E is the master inhibitor of oxidation of the bad cholesterol LDL - which is believed to be the first step in atherosclerosis.  
Vitamin E is more than the master antioxidant, it has additional important functions. For example:
  1. Vitamin E inhibits the activity of the enzyme PKC (protein kinase C) which is associated with inflammation.
  2. Vitamin E exhibits anticoagulant properties. Oxidized alpha-tocopherol (called alpha-tocopheryl quinone) is also a powerful anticoagulant.
  3. Vitamin E compounds reduce the production of inflammatory compounds such as prostaglandins.
  4. Tocotrienols and gamma-tocopherol have other unique functions.
The main sources of vitamin E in the diet are vegetable oils (especially safflower oil, sunflower oil, and cottonseed oil), green leafy vegetables, nuts, cereals, meats, egg yolks, wheat germ, and whole wheat products. Vitamin E deficiency is rare and occurs almost exclusively in people with an inherited or acquired condition that impairs their ability to absorb this vitamin.

Table: Recommended Dietary Allowances (RDAs) for Vitamin E (Alpha-Tocopherol) [4]

* Adequate Intake (AI)

Table lists the RDAs for alpha-tocopherol in both mg and IU of the natural form; for example, 15 mg x 1.49 IU/mg = 22.4 IU. The corresponding value for synthetic alpha-tocopherol would be 33.3 IU (15 mg x 2.22 IU/mg).

Symptoms of vitamin E deficiency include muscle weakness, visual problems (especially at night), and a poor sense of balance. Over a long period, vitamin E deficiency may progress to blindness, heart disease, and impaired thinking. Supplements are usually only necessary or recommended for people with vitamin E deficiency or a condition that puts them at risk for this deficiency. [5] Possible Risks of Vitamin E Use include increased bleeding and inhibition of clotting function (if taken in excess of 1,000 mg/day). And, some studies indicate an increase risk of heart problems among people who are taking high doses of vitamin E (more than about 300 mg/day). Vitamin E has no known side effects when taken in moderate doses. It’s rare for anyone to be allergic to Vitamin E. But if you do experience a severe reaction (rash, itching, swelling, severe dizziness, trouble breathing) see a doctor immediately. [6]

Vitamin E, a potent peroxyl radical scavenger, is a chain-breaking antioxidant that prevents the propagation of free radical damage in biological membranes. Scientist consider the evidence for potential sites in cellular metabolism and signal transduction where vitamin E may have a structure-specific role in addition to its antioxidant function. The roles of tocopherol-binding proteins in cellular trafficking of vitamin E, especially the incorporation of RRR-alpha-tocopherol into nascent lipoproteins, and the delivery of RRR-alpha-tocopherol to the nucleus are considered. [7] Scientists are investigating whether, by limiting free-radical production and possibly through other mechanisms, vitamin E might help prevent or delay the chronic diseases associated with free radicals. [8]

Perhaps not surprisingly, vitamin E which has been touted to be potentially beneficial for a variety of disorders, including cancer, heart disease, and Other health benefits of vitamin E, based on its function as an antioxidant. [9] The most reliable studies on this issue are controlled clinical trials, such as a large 1994 study of antioxidant vitamins and cancer conducted by the National Cancer Institute (NCI) and the National Public Health Institute of Finland. The study was designed to find out whether antioxidant vitamins in higher doses than the RDA (50 milligrams) could reduce the incidence of lung cancer, other types of cancer, and other illnesses among 29,000 male smokers. The study found no beneficial effect of vitamin E supplements on lung cancer incidence. It found lower rates of prostate and colorectal cancer among those who received vitamin E, but higher rates of bladder, stomach, and other types of cancer. [10,11]

Vitamin E has been linked to the prevention of cardiovascular disease (CVD) based on the hypothesis that oxidation of LDL initiates the development of atherosclerotic plaque. This hypothesis, although not universally accepted, is supported by studies in vitro, in animals, and in humans. This background in basic science and a number of epidemiological studies, led to the initiation of clinical intervention trials.

G. Oriani et. al. in their study suggest that vitamin E plays an important role in the regulation of serum concentrations of cholesterol and lipoproteins in weanling rabbits. Consequently, the maintenance of an adequate nutritional status of vitamin E in the postweaning period is important to avoid alterations of serum lipid pattern ( J Anim Sci. 1997 Feb;75(2):402-8.) [12].

Support for the role of vitamin E in heart disease prevention has come from observational studies, particularly 2 cohort studies which were published in 1993. In the 1st study, the Nurses' Health Study, the researchers concluded that among 83,234 middle-aged women who participated in the study, there was a 40% reduced risk of coronary artery disease for those who took vitamin E supplements compared to those who did not (New England Journal of Medicine 1993;328: 1444-9). The 2nd study, the Health Professionals Follow-up Study, involved over 39,000 males and showed evidence of a significant association between a high intake of vitamin E from supplements and a lower risk of heart disease (New England Journal of Medicine 1993; 328:1450-1456). [13]

The following is a very brief overview of the role of vitamin E in wellness and disease prevention, Andreas M. Papas, Ph.D in NutriNews, January/February 2008 to explain other health benefits of vitamin E including Alzheimer’s disease, aging and immunity, cataracts, and skin health.
  1. Alzheimer’s disease: A collaborative study at major medical centers across the United States found that in Alzheimer’s patients taking large doses of vitamin E (2,000 IU/day), progression of the memory-robbing disease was delayed by approximately seven months.
  2. Aging and immunity: Studying healthy elderly people, researchers at Tufts University, reported that vitamin E increased the power of disease-fighting T-cells, improved delayed-type hypersensitivity skin response (DTH) by 65 percent and antibody response to hepatitis B six-fold. It also increased significantly the antibody titer to tetanus vaccine. A recent study in Netherlands reported no benefit in acute respiratory tract infections in elderly person from vitamin E supplementation.
  3. Cataracts: A Canadian study compared the consumption of vitamin supplements by 175 cataract patients with that of 175 cataract-free controls. People in the control group were taking significantly more supplements of vitamins C and E than the cataract group.
  4. Skin health: Vitamin E has been shown to reduce the damage to skin from exposure to UV radiation and ozone. 

Updated : Benefits of Vitamin E

Saturday, January 23, 2010

Sjögren's Syndrome

Sjögren's Syndrome


Other names : Mikulicz syndrome, Sicca syndrome

Sjögren's (pronounced SHOW-grins) syndrome is a chronic autoimmune disease in which a person’s white blood cells attack their moisture-producing glands. Historically, Mikulicz first reported these symptoms in 1898 so this condition was called "Mikulicz syndrome." It is more commonly named for Henrik Sjögren (1899-1986), a Swedish ophthalmologist, who reported the association of severe dry eyes [keratoconjunctivitis sicca (KCS)], dry mouth and rheumatoid arthritis in 1933. Later, it was recognized that patients might have dry eyes and dry mouth but no rheumatoid arthritis.

Today, according to the National Institute of Neurological Disorders and Stroke (NINDS), between 1 and 4 million people in the United States are living with this disease. The condition is found throughout the world and in all ethnic groups. Most people are more than 40 years old at the time of diagnosis. Women are 9 times more likely to have Sjögren's syndrome than men.

This desease is a disorder of your immune system often defined by its two most common symptoms — dry eyes (its medical term is xeropthalmia; your eyes may burn, itch or feel gritty — as if there's sand in them) and a dry mouth (its medical term is xerostomia; your mouth may feel like it's full of cotton, making it difficult to swallow or speak). In addition, Sjogren's syndrome may cause vaginal dryness that can cause dyspareunia, dryness of the trachea and bronchus (the airways) can lead to a dry cough and chest infections, and dry skin can occur. Sjogren's syndrome may affect other organs of the body including the kidneys, blood vessels, lungs, liver, pancreas, and brain.

The risk for passing this disease on to family members is extremely low. There is a slightly increased incidence of autoimmune diseases in siblings and children. Many women with Sjögren's syndrome are interested in the risks of pregnancy and risks to the baby. Obstetrical authorities report slightly higher rates of recurrent fetal death and congenital heart block in those pregnancies complicated by maternal autoimmune disease.

There are two types of Sjogren's syndrome; primary and secondary. Primary Sjögren's syndrome is when Sjögren's syndrome occurs by itself. Secondary Sjögren's syndrome is when Sjögren's syndrome occurs in association with another autoimmune disease such as rheumatoid arthritis or systemic lupus erythematosus. (Sjögren's syndrome affects 5 out of 10 people who have rheumatoid arthritis.)

The cause of Sjögren's syndrome is not known, but it is considered an autoimmune disorder. People with this disease have abnormal proteins in their blood suggesting that their immune system, which normally functions to protect the body against cancers and invading infections, is reacting against their own tissue. As note, Sjögren’s syndrome causes increased levels of IL-1RA in CSF suggesting increased activity in the Interleukin 1 system and that this is associated with increased fatigue through cytokine induced sickness behavior.

Sjögrens syndrome is marked by lymphocytic infiltration of the lacrimal and salivary glands. Extra-glandular manifestations are common and result from similar infiltration of various organs. Immunohistologic studies have shown that the lymphocytic infiltrate is comprised predominantly of CD4-positive T cells, primarily of the Th1-type. Unlike normal epithelium, the glandular epithelial cells express MHC class II antigens and B7 co-stimulatory molecules, allowing them to serve as antigen-presenting cells.

Diagnosis of Sjögren's syndrome; The doctor needs to take a good history, seeking out features of dryness. The physical examination is helpful looking at the eyes and the mouth and observing whether they are dry, red and irritated and the skin is dry. A specialist eye examination is valuable and occasionally kidney and lung function tests are needed. Dry mouth and eyes alone may result from aging, medication or a condition known as Amyloidosis. Blood Tests for diagnosis include : ANA (Anti-Nuclear Antibody), SS-A (or Ro) and SS-B (or La) Antibodies to SS-A (or Ro) and SS-B (or La.), RF (Rheumatoid Factor), ESR (Erythrocyte Sedimentation Rate), IGs (Immunoglobulins). The Salivary Gland Tests include: Parotid Gland Flow, Salivary Scintigraphy, Sialography.

Treatment of this disorder is based on the symptoms. Dry eyes are treated with artificial tears, a tear stimulant, or eye lubricant. Dry mouth may be helped by frequent small drinks of water or chewing gum to stimulate saliva production. Arthritis symptoms are treated with anti-inflammatory medicines, such as aspirin, acetaminophen, and other NSAIDs.

These are the medications used to relieve the dryness caused by the Sjögren autoimmune attack on the body’s moisture-producing glands on table below [1].


Treatment of Sjögren's syndrome is aimed at symptomatic relief, at this stage there is no cure [2].

Dry Eyes
A variety of artificial tear preparations can be used to treat dry eyes. The severity of the dryness will determine how frequently you need to use the drops. Some preparations have preservatives - these last longer but may be irritating to the eye. It is a matter of trying one brand and seeing how you go. Lubricating ointments are longer acting preparations that are useful at night whilst sleeping. These tend to be greasy so are not appropriate for daytime use.

Dry Mouth
Dry mouth is harder to treat than dry eyes. There are some artificial oral lubricant preparations available, but none are entirely satisfactory. Some people find chewing sugarless gum is helpful, whilst others prefer simply to spray water into the mouth. Dietary modification using soft or moist foods may be of some assistance. The use of sugar should be avoided as it contributes to the development of dental caries. Good dental hygiene and frequent dental visits are essential.

Dry Skin
Sorbolene cream and moisturisers may be helpful. For dryness of the vagina, lubricating creams or oestrogen creams may be helpful.

Oral Medications
Oral medications are used in a majority of people. Non-steroidal anti-inflammatory drugs, or the anti-malarial drug Plaquenil, may be used to treat joint symptoms. Prednisone and immunosuppressant drugs are seldom used but are useful where there is severe lung or kidney involvement.

In an era of increasing health maintenance organizations (HMO's) and the need for diagnosis codes, it is often necessary for the patient to help their physician or dentist by informing them of currently accepted diagnosis codes. Individuals should consult a qualified health care provider for professional medical advice, diagnoses and treatment of a medical or health condition.